Pit & Quarry, May 2014

Idea from space Less carbon emissions means a more environmentally friendly way to drill and less fuel use means cost savings Y BY PATRICK MAHONEY oure kicked back in your favorite recliner watching a documentary on the Space Shuttle and suddenly theyre talking about on board pneumatic systems Who wouldnt be excited A certain engineer was not only excited he was inspired A compressor hasnt got any air to compress in the vacuum of space and I thought how much power does it take to rotate the compressor in a vacuum The answer Only enough power to overcome the frictional forces inside the compressor such as bearings and rotor mesh friction He was on to something Now our engineer may sound like someone who needs to stop taking work home but fortunately for his employer he hasnt yet Grant Field automation engineering manager for Sandvik Mining recognized that operating in a vacuum could reduce engine load Sandvik doesnt operate on the moon however Field needed a way of creating a vacuum inside a compressor or you might say of creating space inside a compressor He thought of connecting a small compressor to the main compressor Using the appropriate valves he could evacuate the main compressor to isolate it Isolating the compressor Field explains means isolating the inlet from the atmosphere and the outlet from the pressure in the receiver tank where compressed air is stored at a higher pressure than the atmosphere Field wrote a proposal based on his concept that showed a theoretical fuel savings of more than 30 percent That got managements attention First try Sandvik developed the technology in house using existing components such as a compressor from an underground drill modifying the components to suit the application It took us around three months to identify the correct components and how to install them It took a week to fit the parts to SAFETY ENVIRONMENTAL CMS replaces all pneumatic regulation with electronic valves and controls that have proved reliable and make start up easier a machine The concept worked on the first attempt Field says We then spent another two months fine tuning the components and the programmable logic controllers to get the system to work as we wanted it to Specifically we wanted all of the components to be fail safe Our prime concern was that if any part should fail the machine would either shut down or default to a condition that would not damage the main compressor or the other systems he says After successful testing of the concept on a DR460 rotary blasthole drill in the factory they secured a prototyping site in Australia and continued development After a year of successful field testing Sandvik moved its compression management system CMS to production installations The company now has more than 50 systems in operation The list price of the system is 180000 plus installation Two mechanics take three days to fit the hardware and it takes one electrician two days to wire it Once installed programming and commissioning take about four hours All of the original pneumatic controls are removed from the compressor and new controls and evacuation compressor are fitted along with new valves and wiring 16 PIT QUARRY May 2014 www pitandquarry com